How to make something similar to rigid body joint in Cycles?
The game engine rigid body joints do not work outside the game engine. For similar behaviour in Cycles you should use Rigid Body Constraints - these can be created by selecting two or more rigid bodies and clicking Connect in the Physics Toolbox panel (T). When a rigid body constraint is first added it defaults to ‘Disable Collision’ - to enable collision between linked objects you should untick the checkbox in the Rigid Body Constraint physics properties.